Abstract
In 2019, a multi-cohort population of the typically estuarine burrowing shrimp Neotrypaea sp., was discovered approximately 7 miles offshore of Newport, Oregon. Morphological analysis of the offshore population, microbial sediment sequencing, and species distribution modeling was conducted with this new offshore population. In order to identify Neotrypaea sp. to the species level, morphological comparisons were conducted among the offshore population and two estuarine species found in Yaquina Bay – N. californiensis and N. gigas. Previously established characteristics and novel characteristics were identified and measured on ImageJ. The majority of characteristics between N. gigas and the offshore Neotrypaea were not significantly distinctive except for the parts of the eyestalk. Furthermore, to investigate potential cues for the Neotrypaea to settle in this new deeper-water environment, the sediment microbial communities were examined. Surface sediment was collected from offshore and estuary locations with and without Neotrypaea sp. DNA was extracted from the sediment samples and sequenced using Illumina MiSeq. Bacteria of the genus Shewanella, which have been shown to induce oyster and mussel settlement and metamorphosis, were found in both the estuary and offshore locations and in five times greater abundance with Neotrypaea than without. Species distribution models were run using both presence-absence data (Boosted Regression Trees, BRT) and presence-only data (MaxEnt). Environmental data for those models included course-grained layers (9km2), intermediate layers (2 km2) and fine-grained layers (25m2), as well as in situ data. The BRT with fine-grained layers and in situ data performed the best. Models predicted some areas of high probability of occurrence offshore Oregon and southern Washington, and ground-truthing was conducted at 11 locations. Over 120 Neotrypaea sp. were collected offshore Neskowin and Nehalem, OR.